JPS5834922B2 - Tansoutanmakihen Atsukino Denatsuchiyouseihoshiki - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention aims to make effective use of a 3-button on-load tap changer, and is capable of connecting the primary and secondary sides of a single-phase autotransformer with a single 3-button on-load tap changer. The present invention relates to a voltage adjustment method for a single-phase autotransformer that allows adjustment of the voltage on the tertiary side.

A transformer 9 that interconnects ultra-super high voltage and ultra-high voltage, for example 500/
A single-phase autotransformer is used for the 275KV transformer in order to reduce transportation weight and ensure insulation distance between lines.

Considering the importance of these transformers, conventionally,
For example, as shown in Fig. 1, each phase U2V, W autotransformer 1
Load tap switching device for each 3 buttons between ~3 and neutral point 4~
6, each one phase portion 4a to 6a are connected.

In addition, each tap winding corresponding to each one phase portion 4a to 6a is as follows:
A voltage is induced by each excitation winding excited by the tertiary winding.

In this case, as a characteristic of the autotransformer, when the primary or secondary voltage is adjusted, the tertiary voltage also fluctuates as described below.

(However, the phase relationship does not change.) In other words, the primary of the autotransformer,
The secondary and tertiary side voltages are each E□.

E2. E3. The number of series, shunt and tertiary windings is n, n
.

SC If no, then As a result, the tertiary side voltage E3 decreases.

Since this tertiary winding is generally connected to a substation load or a phase adjustment load, it is undesirable for the voltage to change.

For this reason, it is necessary to further provide a separately installed load dark voltage regulator 7 in the tertiary circuit.

However, due to marketability, on-load tap changing devices are rarely available for single-phase applications, and are generally designed for three-phase transformers. When adjusting the voltage of 3-phase on-load tap switching device 4
~6, the one phase portion 4a~6a is the two phase portion 4a~
6a, 4b to 6b are connected between the single-phase autotransformer and the neutral point, so the remaining two phases 4b to 6b, 4c to 6c
Alternatively, the one-phase portions 4c to 6c become idle, resulting in a very poor utilization rate of the tap changer under load.

In addition, only one load tap switching device 4 for three buttons is used.

Each phase 4a to 4c is connected to each single phase autotransformer 1 to 3.
It is also conceivable to connect the transformer between the transformer and the neutral point, but this is not practical in the case of an ultra-high voltage transformer to which the present invention is applied, since the capacity would be insufficient.

This invention was made by focusing on the points mentioned above.
By using the remaining phase of the three-button on-load tap changer, which is in an idle state, to adjust the voltage on the tertiary side of a single-phase autotransformer.

The object of the present invention is to provide a voltage adjustment method for a single-phase autotransformer that allows effective use of an on-load tap changer.

Hereinafter, one embodiment of the present invention will be described based on FIG. 2.

In the embodiment shown in Fig. 2, each of the remaining one phase portions 4b to 6b, in which the load tap changer for each of the three buttons is in an idle state, is placed outside the tertiary side △ circuit of a single-phase autotransformer. The excitation windings of each phase 4b to 6b are connected in a star shape in order to match the phases.

Note that the tertiary side circuit in Figure 2 is a direct type in which the load current is directly switched by the tap switching device, but due to the switching ability of the tap switching device and the interphase dielectric strength, the current rating may differ from the single circuit voltage. It goes without saying that the present invention can be applied to an indirect type in which a series transformer is used for transformation as necessary to match the rating of the tap changer.

In addition, the tertiary side circuit in Fig. 2 is connected to △, and each of the remaining one phase 4b to 6b with an idle state is connected to the outside.
are connected to each other, but it is not limited to this and may be connected to Y, in which case 4b to 6b
is inserted in series in the tertiary coil of each phase.

Furthermore, the embodiment shown in Fig. 2 is a case where three single-phase single-winding transformers are used, but if one single-phase single-winding transformer is used, 4b should be connected in series with the tertiary coil. Just insert it.

As described above, according to the present invention, when there is insufficient current capacity for each one phase or two phases of the load tap changer for three buttons between the single-phase autotransformer and the neutral point, are connected in parallel, or in series if the regulated voltage ranges over a wide range, to adjust the voltage on the primary side or secondary side of each single-phase autotransformer, and also to adjust the voltage of the 3-button on-load tap changer. By connecting the remaining two phases or one phase to the tertiary side of the single-phase autotransformer and adjusting the voltage on the tertiary side of each single-phase autotransformer, it is possible to It is possible to provide a voltage adjustment method for a single-phase autotransformer that allows effective use of an on-load tap changer.

[Brief explanation of the drawing]

FIG. 1 is a wiring diagram showing a conventional voltage regulating system for a single-phase autotransformer, and FIG. 2 is a wiring diagram showing an embodiment of the present invention. The same symbols indicate the same contents throughout each drawing, and 1 to 3 are U
, V, and W phases, and 4 to 6 are on-load tap switching devices for three buttons.

Claims (1)

[Claims] 1 Connect one phase or two phases of a three-button on-load tap changer between the single-phase autotransformer and the neutral point to connect the primary side or two of the above single-phase autotransformers. At the same time, the remaining two phases or one phase of each of the above-mentioned 8-phase on-load tap changers are connected to the tertiary side of the single-phase autotransformer. A voltage adjustment method for a single-phase autotransformer, characterized in that the voltage on the tertiary side of the phase autotransformer is adjusted.